1. Field of the Invention
The present invention relates to a color-converting device for converting an input color signal in an input-side color space into an output color signal in an output-side color space.
2. Description of Related Art
Normally, a color reproducible range (gamut) on a color CRT monitor is different from that of a color printer. Accordingly, in order to convert RGB (red, green, blue) color signals for a color CRT monitor into CMYK (cyan, magenta, yellow, black) color signals for a color printer, an RGB-RGB conversion process (color matching) is performed to correct this difference before performing an RGB-CMYK conversion process.
Color signal conversion methods that employ a color conversion table are in wide use today. For example, the color conversion table stores therein CMYK values for reproducing RGB values at grid or lattice points defined in the RGB color space. CMYK values for reproducing RGB values that do not fall on the grid points are determined through interpolation based on CMYK values corresponding to the grid points.
Methods commonly used for determining output values through interpolation involve selecting four through eight grid points around the target point (hereinafter referred to as the conversion point). Some such interpolation methods well known in the art include a method using a cube disclosed in United States Patent Application Publication No. 2001/33288A1 and a method using a triangular pyramid disclosed in U.S. Pat. No. 6,571,010.